In a recent Kliman Online chat (and today's, too), a debate blew up about whether to base a server’s tip on the pre-or post-tax amount. Todd Kliman responded: “Pre-tax. Always pre-tax.” But over the next couple of weeks, there was an uproar from former servers who claimed they felt slighted if they received anything less than 20 percent on a post-tax bill.

What’s your take on tipping? Do you base it on the pre- or post-tax amount? Do you tip 15 or 20 percent?